Watercraft using narrowing concave channels

Abstract

The invention is a watercraft with at least one hull which creates hydrodynamic lift by using narrowing concave channels ( 1 ) on the underside of the said at least one hull where propulsion ( 3 ) is placed such that the said propulsion draws water through the said narrowing concave channels ( 1 ).

What is claimed is: 
     
       1. A watercraft comprising:
 at least one hull; and 
 at least one depression on the underside of the at least one hull, the at least one depression forming two channels having a planing pad between the two channels; wherein: the at least one depression is located completely below the static waterline; 
 the centre of gravity (CG) of the watercraft is located longitudinally at the widest lateral point of the depression or between the widest lateral point of the depression and the narrowest lateral point of the same depression; and 
 the lateral width at any point of the depression at a stern longitudinal section of the watercraft is narrower than the widest lateral point of the depression such that a most forward portion of the at least one depression spans a majority of a width of the at least one hull and such that a most rearward portion of the at least one depression spans less than the majority of the width of the at least one hull. 
 
     
     
       2. A watercraft as in  claim 1  where for each of the at least one hull, a longitudinal side of the depression closest to the port side of each hull and a longitudinal side of the depression closest to the starboard side of the same hull are symmetrical in depth. 
     
     
       3. A watercraft as in  claim 1  where the at least one depression has at least one entrance at a bow side of the depression such that water can flow horizontally into the depression. 
     
     
       4. A watercraft as in  claim 3  where the at least one depression has at least one exit at a stern side of the depression such that water can flow horizontally out of the depression thereby forming at least one channel on the underside of the watercraft hull for water to flow through freely. 
     
     
       5. A watercraft as in  claim 4  where the combined widths of lateral cross sections of the at least one entrance is greater than the combined widths of the lateral cross sections of the at least one exit. 
     
     
       6. A watercraft as in  claim 4  further comprising at least one water propulsor that forces water through the at least one channel. 
     
     
       7. A watercraft as in  claim 5  where the lateral cross section in at least one longitudinal portion of the at least one channel is concave in shape. 
     
     
       8. A watercraft as in  claim 4  where at least a longitudinal section along a channel of the at least one channel varies in depth. 
     
     
       9. A watercraft as in  claim 1  further comprising at least one movable control surface attached to the at least one hull. 
     
     
       10. A watercraft as in  claim 1  where the at least one depression has at least one exit at a stern side of the depression such that water can flow horizontally out of the depression thereby forming at least one channel on the underside of the watercraft hull for water to flow through freely. 
     
     
       11. A watercraft as in  claim 10  further comprising at least one water propulsor that forces water through the at least one channel. 
     
     
       12. A watercraft as in  claim 10  where the lateral cross section in at least one longitudinal portion of the at least one channel is concave in shape. 
     
     
       13. A watercraft as in  claim 10  where at least a longitudinal section along a channel varies in depth. 
     
     
       14. A watercraft comprising:
 at least one hull; and 
 at least one depression on the underside of the at least one hull, the at least one depression forming at least one channel, at least one hinged flap disposed in the at least one channel; wherein: the at least one depression is located completely below the static waterline; 
 the centre of gravity (CG) of the watercraft is located longitudinally at the widest lateral point of the depression or between the widest lateral point of the depression and the narrowest lateral point of the same depression; and 
 the lateral width at any point of the depression at a stern longitudinal section of the watercraft is narrower than the widest lateral point of the depression such that a most forward portion of the at least one depression spans a majority of a width of the at least one hull and such that a most rearward portion of the at least one depression spans less than the majority of the width of the at least one hull. 
 
     
     
       15. The watercraft of  claim 14 , wherein the at least one depression has at least one entrance at a bow side of the at least one depression such that water can flow horizontally into the at least one depression. 
     
     
       16. The watercraft of  claim 15 , wherein the at least one depression has at least one exit at a stern side of the depression such that water can flow horizontally out of the depression thereby forming the at least one channel on the underside of the watercraft hull for water to flow through freely. 
     
     
       17. The watercraft of  claim 16 , wherein the combined widths of lateral cross sections of the at least one entrance is greater than the combined widths of the lateral cross sections of the at least one exit. 
     
     
       18. The watercraft of  claim 16  further comprising at least one water propulsor that forces water through the at least one channel. 
     
     
       19. The watercraft of  claim 17 , wherein the lateral cross section in at least one longitudinal portion of the at least one channel is concave in shape. 
     
     
       20. The watercraft of  claim 16 , wherein at least a longitudinal section along a channel of the at least one channel varies in depth.